CVE-2013-4769 in Eucalyptus
Summary
by MITRE
The cloud controller (aka CLC) component in Eucalyptus 3.3.x and 3.4.x before 3.4.2, when the dns.recursive.enabled setting is used, allows remote attackers to cause a denial of service (traffic amplification) via spoofed DNS queries.
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Analysis
by VulDB Data Team • 03/28/2019
The vulnerability identified as CVE-2013-4769 affects the cloud controller component within Eucalyptus cloud infrastructure versions 3.3.x and 3.4.x prior to 3.4.2. This flaw specifically manifests when the dns.recursive.enabled configuration setting is active, creating a significant security risk that can be exploited by remote attackers to execute traffic amplification attacks. The issue represents a critical weakness in the distributed cloud computing environment's network infrastructure, potentially compromising the availability and performance of cloud services.
The technical flaw stems from the improper handling of DNS recursive queries within the cloud controller's network processing pipeline. When the dns.recursive.enabled parameter is configured, the system accepts and processes DNS queries that can be spoofed by malicious actors. This misconfiguration allows attackers to send forged DNS requests with spoofed source IP addresses, causing the cloud controller to forward responses to the spoofed addresses rather than the actual requester. The vulnerability operates at the network layer, leveraging the fundamental DNS protocol characteristics where recursive resolvers are designed to forward queries to authoritative servers, creating an amplification effect that can overwhelm network resources.
The operational impact of this vulnerability extends beyond simple service disruption, creating a potential vector for large-scale denial of service attacks that can significantly impact cloud infrastructure availability. Attackers can leverage this weakness to amplify their network traffic, potentially using small query packets to generate much larger response packets that flood target systems. This amplification factor can reach ratios of hundreds to one, making it particularly dangerous for cloud environments where network resources are shared across multiple tenants. The vulnerability directly affects the cloud controller's ability to maintain stable network operations and can result in cascading failures that impact the entire cloud infrastructure.
This vulnerability aligns with CWE-400, which categorizes it as an "Uncontrolled Resource Consumption" or "Denial of Service" weakness, specifically related to resource exhaustion through network traffic amplification. The attack pattern corresponds to techniques documented in the MITRE ATT&CK framework under the T1498 category for "Network Denial of Service" and T1071 for "Application Layer Protocol" where DNS protocols are exploited for malicious purposes. Organizations implementing Eucalyptus cloud solutions must consider this vulnerability as part of their comprehensive security posture assessment, particularly in environments where DNS recursive services are enabled and network traffic monitoring is insufficient.
The recommended mitigations include immediate patching to version 3.4.2 or later, where the vulnerability has been addressed through proper DNS query validation and source address verification mechanisms. System administrators should disable the dns.recursive.enabled setting when not explicitly required for operational purposes, implementing strict network access controls and monitoring for anomalous DNS traffic patterns. Network segmentation and rate limiting should be implemented to prevent excessive DNS query processing, while continuous monitoring of network traffic for amplification patterns helps detect potential exploitation attempts. Additionally, organizations should conduct regular security assessments of their cloud infrastructure configurations to identify and remediate similar vulnerabilities that may exist in other components of their distributed systems.